Various frozen confectionery products containing inclusions or crispy layers of a fat-based coating exist.
U.S. Pat. No. 5,135,767 discloses to make a cup or a cone having a flaky texture, superposed ribbons of ice cream and chocolate are extruded into a mold in the form of spirals by means of an extrusion assembly comprising a flat extrusion tube and a spray tube. The extrusion assembly receives a spinning movement resulting from an eccentric rotational movement and an ascending movement relative to the mold.
However, as the chocolate is sprayed onto the ice cream, it is very difficult to control the thickness of the chocolate layers and virtually impossible to obtain regular crunchy layers of a desired thickness. Furthermore the spraying mechanism is relatively expensive.
In U.S. Pat. No. 5,283,070 a layered cone with alternating layers of chocolate and ice cream is made by extruding an ice cream into a vertically descending helix rotating about a vertical axis and having spaced flights which define passages therebetween the helix. Chocolate is sprayed into these passages of the extruded helix. Here also it is very difficult to control the thickness and crunchiness of the chocolate layers, and the apparatus is rather expensive due to the spraying process.
U.S. Pat. No. 5,603,965 relates to the production of cakes of ice confectionery containing integrated decorative layers of crisp material such as chocolate. The ice cream is horizontally extruded, and chocolate is sprayed on an ice cream layer. Here also it is difficult and costly to control the thickness of the chocolate layers.
EP 0 221 757 A2 discloses an ice cream product containing chocolate flakes. The ice cream is extruded from a nozzle into a cone or a mold, and chocolate is ejected with high speed towards a stream of ice cream issued from the nozzle so as to penetrate the ice cream and form a thin strip like layer therein. It is not possible to obtain a regular, layered structure with such a method.
Other methods for producing layered ice cream products are known from prior art where the chocolate stays relatively long in contact with the ice cream, e.g. using a chocolate nozzle rotating inside an ice cream flow. These methods do not work with real chocolate, which has a higher melting point than fat-based coatings and will thus quickly clump.